(1) Field of the Invention
The present invention relates to an image forming apparatus, such as a copier, a multifunction machine, a laser printer, facsimile machine or the like, for performing an image forming process based on electrophotography by using developer such as toner, in particular, relating to an image forming apparatus capable of exchanging a toner container storing toner.
(2) Description of the Prior Art
In the image forming apparatus such as a multifunction machine or the like, the image forming process has a developing process in which an electrostatic latent image on a photosensitive drum is developed with toner in a developing unit, a transfer process in which the toner image is transferred on a sheet, and a fixing process in which the toner image is fixed to the sheet in a fixing portion.
Since the toner need to perform the image forming process, proposed are various techniques for performing a display control of remaining toner and a detection control of remaining toner.
Regarding the detection of the remaining toner, in Patent Document 1, photosensors are installed inside a developing tank in a developing unit, and the remaining toner information is detected by the photosensors and displayed in a display such as an operation panel.
However, being based on the information of amount of toner in the developing tank, there is a time that it becomes unclear whether the toner in a toner cartridge (toner storing container) is used up or not, and it is impossible to completely prevent the toner in the toner cartridge from remaining.
In spite of the fact that the toner in the toner storing cartridge is not used up, a user judges that the toner has been used up, and the user exchanges the toner cartridge to new one. As a result, the remaining toner in the exchanged toner cartridge is threw away.
Therefore, in the conventional manner, there was a problem that the toner is not used up by the user.
As to the problem, desired is a method for making the user recognize the remaining toner within the toner cartridge visually and easily and requested is a technic with which the user can confirm that the toner within the toner cartridge is used up to the end. However, an effective technique was not suggested conventionally.
There is no scheme for reducing the remaining toner, there is no scheme for detecting the remaining toner exactly, and there is no scheme that it is prevented the toner cartridge from being drawn until the toner is used up. As a result, it is necessary for the user to absolutely perform a drawing operation for drawing the toner cartridge at each image forming operation in order to visually confirm how much of the remaining quantity of toner.
As a matter of course, since it is impossible to perform the drawing operation during a printing process, the drawing operation must be done except when the printing process is being performed, causing inconvenience.